This invention relates to power supplies.
In one type of power supply, the output is a high voltage and the power supply selectively maintains constant current, constant voltage or constant power output under the control of a feedback circuit. In such power supplies, the panel controls which may be handled by an operator are insulated from the high-voltage section. Isolation from the high voltage is generally obtained through high resistances, complete high voltage insulation of the low voltage circuitry and a power transformer with high voltage insulation on all of the secondary windings. Some such power supplies provide power to more than one channel.
In the prior art power supplies of this class, there is difficulty in obtaining current feedback for constant current operation and constant power operation. The difficulty occurs because of the need for insulation to meet safety standards between the high-voltage section of the power supply and controls, such as those on microprocessors that are used in some feedback systems. Moreover, some power supplies have multiple outputs and measurements of load current or power in a single output is difficult because the measurement of current or power in only one channel may reduce the feedback current signal and cause the power supply to attempt to compensate.